1. Field of the invention
The present invention relates to an optical component composed by arraying a plurality of optical fibers.
2. Related Background Art
As an optical component for transmitting optical images, an optical component formed by arraying a plurality of optical fibers is widely known. The optical component has an incident plane and an exit plane exposing the core and clad of each optical fiber, and the optical image entering the incident plane is transmitted to the exit plane.
This optical component has numerous benefits including a high transmission efficiency and a smaller in size of optical system as compared with the lens, and is hence used in various fields such as fingerprint detecting system.
The optical component is usually manufactured by arraying and bundling a plurality of optical fibers in circular or square section, and forming integrally. Therefore, due to pressure at the time of integral forming, the section of the core of optical fibers for composing the optical component is transformed into polygonal shapes having mutually parallel diagonals such as square and hexagon, and the following problems occur.
That is, the light entering the incident plane with a specific incident angle is reflected repeatedly on the mutually parallel diagonals, and leaves the exit plane with a specific exit angle. As a result, a pattern having an intensity only in a specific exit angle is formed on the output image emitted from the exit plane, and this pattern becomes noise to lower the resolution of the optical component.
It is hence an object of the invention to solve such problems and prevent occurrence of pattern noise, and present an optical component of high resolution.
To solve the problems, the optical component of the invention is an optical component formed by arraying a plurality of optical fibers, in which each optical fiber comprises a first core, a second core formed around the first core and having a smaller refractive index than that of the first core, and a clad formed around the second core and having a smaller refractive index than that of the second core.
Since each fiber has the first core and the second core having a smaller refractive index, if the light enters the incident lane at a specific incident angle, the light entering the first core and the light entering the second core are different in the path of light progress, and it prevents formation of pattern having an intensity only in a specific exit angle. As a result, pattern noise is prevented, and an output image high in resolution can be obtained.